Multistage compression system
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Solution Overview
Problem
In multistage compression systems, the uneven distribution of oil across compressors affects refrigerant circuit efficiency, particularly when pressure reducing elements like intercoolers or refrigerant merging points are introduced, leading to variations in refrigerant and oil flow, which can result in insufficient cooling.
Innovation Solution
The oil discharge pipe is connected to the refrigerant pipes upstream of the pressure reducing element, such as an intercooler or merging point, to control the amount of oil discharged and maintain appropriate oil levels in the low-stage compressor, ensuring balanced oil distribution and efficient refrigerant flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the oil discharge pipe is connected downstream of the pressure reducing element (intercooler), then the oil can be discharged after refrigerant cooling, but the amount of refrigerant bypassing the intercooler increases causing insufficient cooling
Solution Approach 1:
The oil discharge pipe is connected to the refrigerant pipe upstream of the pressure reducing element (intercooler), allowing oil to be discharged before the refrigerant passes through the intercooler. This preliminary positioning prevents refrigerant bypassing and ensures adequate cooling while controlling oil discharge amount.
2Ease of operation
If the oil discharge pipe connects to downstream of the pressure reducing element, then oil discharge is facilitated, but the amount of oil discharged varies greatly affecting refrigerant circuit
Solution Approach 1:
The connection position of the oil discharge pipe is changed from downstream to upstream of the pressure reducing element. This parameter change in positioning controls the oil discharge amount by utilizing the pressure difference before the pressure reduction, preventing excessive or deficient oil distribution in the refrigerant circuit.
3Temperature
If a pressure reducing element is provided in the refrigerant pipe, then refrigerant cooling is achieved, but the pressure reduces causing variable oil discharge amount
Solution Approach 1:
The refrigerant pipe is segmented into upstream and downstream sections relative to the pressure reducing element. The oil discharge pipe is connected to the upstream section, separating the oil discharge function from the pressure reduction zone. This segmentation allows independent control of oil discharge amount while maintaining refrigerant cooling functionality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces the amount of oil discharged, allowing for precise control of oil levels in the low-stage compressor, enhancing refrigerant circuit efficiency and preventing excessive or deficient oil distribution, thereby improving system performance.
Implementation Method 1
the pressure reducing element reduces a pressure of the refrigerant flowing through the refrigerant pipes
Implementation Method 2
The oil discharge pipe connects the low-stage compressor and a portion of the refrigerant pipes, which is an upstream side of the pressure reducing element
Data Source
AI summary
A multistage compression system uses refrigerant and oil. The multistage compression system includes a low-stage compressor that compresses the refrigerant, a high-stage compressor that further compresses the refrigerant compressed by the low-stage compressor, refrigerant pipes that introduce the refrigerant compressed and discharged by the low-stage compressor into a suction part of the high-stage compressor, an intercooler, and an oil discharge pipe. The intercooler cools the refrigerant discharged by the low-stage compressor before the refrigerant is sucked into the high-stage compressor. The intercooler is disposed between the refrigerant pipes. The oil discharge pipe discharges the oil in the low-stage compressor. The oil discharge pipe connects the low-stage compressor and a portion of the refrigerant pipes. The portion of the refrigerant pipes is on an upstream side of the intercooler.